Post by kagetsume on May 7, 2020 9:30:48 GMT -5

I've been using neopixels for all my saber builds with the I3 boards. I love the effect. But, I always seem to get noise from the neopixels on the speaker; a sort of high-pitched whine that varies with the neopixel brightness. I'd love to filter this out/clear it. Does anyone have any suggestions for how to reduce this noise, perhaps through a noise filter between the positive and ground lines of the board?

Post by Nerf Herder on May 13, 2020 10:07:39 GMT -5

Post by naigon on May 13, 2020 11:15:55 GMT -5

Are you using the Alotive strips? Not all pixel strips are created equal. The Alotive strips due to the way the chips work create tons of signal noise which can manifest itself as noise on the audio line. That's why I recommend the Sparkfun Skinny strips or the BTF lighting strips as both of those tested with little to no additional noise on the line.

I also only use the good batteries, but I suspect a battery that cannot really handle that high amperage load could create the same issue.

Post by kagetsume on May 14, 2020 19:04:29 GMT -5

I'm using sparkfun skinny strips. I don't use the alotive ones because of many reasons (you noted some of them). The battery I use is a 27100 5100mAh 20A IMR (From Acebeam) It's not a cheap battery in terms of price. (I've run one strip, 2 strip, and 3 strip off it, same result). I've tried other neopixel blades too (One I got with an Electrum saber), and get the same whine-effect. The noise I speak of isn't massive, it's slight, but it's there. It's easily heard if you turn a saber on, then socket and unsocket the blade. When the blade's out, it sounds slightly different than when it's socketed in; there's a slight higher pitched whine that fluctuates with the brightness. I can try to make a recording of the two different sounds if you'd like a comparison. Let me see if I can record what I'm hearing.

Post by kagetsume on May 16, 2020 16:58:18 GMT -5

Hah, fair enough! It's not horrible and it isn't as loud as the recording makes it seem. It's just something I'd like to solve. I get the same thing with BTF RGBW strips too, I just verified, on a setup powered by a 12V to 3.7V 10A converter (Intended for car audio). The type of strip changes it some. I actually tried the 4mm super tiny strip 1515 (I think), in a tri-strip config, and I get it with those as well, It's slightly higher pitched and hissy with those. The Sparkfun skinny strips are what I used in the example video, dual strip, using TCSS connectors, 330 Ohm resistor on the data line.

Post by kagetsume on May 19, 2020 22:47:32 GMT -5

Update: Tried the different 21700 cell (5000mAh, 15A continuous). Same result, same sound. I suspect with this saber it's a combination of the narrower speaker amplifying higher tones than my usual bass speaker coupled with the longer echo chamber amplifying it into a perfect storm to make it much more noticeable. I checked my others that use the KR bass speaker and they have to too, it's much less noticeable due to the different speaker.So, yeah just a perfect storm of hardware + resonance that made me really notice it with this build more than I did in all the others. Anyway, like I noted, it's not horrible. it's slight ... but when you build all your stuff, you always notice every little 'imperfection' glaringly.

Post by kagetsume on May 21, 2020 23:45:19 GMT -5

Depends on the build. I usually use the KR Sabers 8ohm bass speaker(https://bit.ly/2AM6NJD). This build I ended up using a much thinner speaker due to space issues. I bought an empty Fallen Order saber body (Saberforge, I liked the hilt, their wiring not so much so I designed/built my own chassis and wired it fully myself.), and you'd think that for the length you'd have lots of room ... NOPE! It's actually mostly narrow space of less than an inch, save for one place where it's just barely long enough for the 27100 battery that's about 1.2 inches wide. I had to go through about 15 different chassis designs to get one that worked with the larger batteries I prefer to use. Anyway, since I had much more limited space, I had to fall back to the 3MMish thinner style from The Custom Saber Shop (https://bit.ly/36kdePO. Which I know favors highs more than lows generally.

The other thing I ran into that I suspect really made the whine prominent with this build was the Fallen Order hilt has a MASSIVE echo chamber. It's two and a half inches long down the pommel (65mm), and maybe three quarters of an inch wide (It's less, an inch wide (19mm). So you can't really fit much of a speaker down into it or anything. But wow, does it ever amplify volume. I actually am running the 'hum' setting on the NEC at 2 just so it's not deafening. 7 was so loud it was actually painful to turn on and use.

What I may do is jump into Audacity and go through and de-amplify all the sound files I'm using so I can up the actual volume and see if I can somehow push out the whine single. Very unlikely as the end result is likely to be the same current-wise on the line, but ... eh, I've tried everything else. All I'll lose in half an hour of time to try it. Failing that, I'll stuff a cotton ball into the end or print an actual sound baffle to slip in to see if that helps any.

I just finished up another saber for a friend using NEC and the KR speaker and unless I run the volume setting in the NEC config at stupidly low settings, I don't really hear it at all unless I listen very hard. Same for other builds I have of similar configs. I run volume really low, I can pick out the whine, but around 4+ for the hum and such on NEC and I really don't notice it unless I focus and listen hard.

Anyway, I do suspect it's the massive echo chamber on that hilt forcing me to run at such a low volume setting coupled with the thinner speaker that made this build particularly bad.

Post by kagetsume on May 24, 2020 18:40:23 GMT -5

Solved! It was definitely exacerbated by the huge resonance chamber. I designed and printed a split part 'sound damper' I could slide into the chamber that split it into three sections instead of one huge one. I was then able to turn the sound volumes back up to 6/10 on the NEC without it being painfully loud. It also prettymuch eliminates the whine. It's still slightly there, but only if you listen really hard for it. So, after many trials, problem solved. Whew.

auscustomsabers: Too long Tommy TOO LONG! <3 Glad to hear you and yours are doing well! Also glad to see you're still kicking around these dark and dusty halls still! Downunder isn't bad. Interesting watching this Covid and now BlackLivesMatter thing play out. Jun 6, 2020 3:29:06 GMT -5

auscustomsabers: The world has become an interesting place! What's news with you? Any word of Don, Amp, Ray, Stan etc etc? (the old crew)Jun 6, 2020 3:29:53 GMT -5

auscustomsabers: Hiya Melissa! All the exciting things! How are you doing? Thank you for the warm welcome and welcome to you also! Jun 6, 2020 3:30:26 GMT -5

ARKM: I have not seen Amp (Corey) or Ray around here in years. Don pops in every once in a blue moon. I forget who Stan is (sorry Stan).Jun 6, 2020 3:39:14 GMT -5

auscustomsabers: Glad to know that Don is still doing ok! Last i heard from him was over 5 years ago and his health was getting worse :/ Stan used to be... i can't recall his username ;D Any word on Lucien?Jun 6, 2020 3:57:30 GMT -5

auscustomsabers: With that knowledge i am armed to vanish into the night for another half decade or so hahaJun 6, 2020 3:57:56 GMT -5

auscustomsabers: I miss lightsabers man! I miss the wheeling and dealing and trading. I have a handful of crap ones from that dodgy "pach store" and a beloved VV Mitsurugi 3k <3Jun 6, 2020 3:59:58 GMT -5